Brief summary of the paper: In a recent Opinion, Mathot and Dingemanse draw attention to a claimed major assumption of studies linking animal personality and energetics: ‘that the selected measure of [metabolism] is a valid proxy for energetic constraints.’

They argue that unless this assumption is tested, results from many studies are uninterpretable.

We would like to argue that the definition of energetic constraints they propose would make it difficult if not impossible to test this assumption.